Stock by Attributes - Does it work with PHP5?

I have recently upgraded my clients site to 1.3.7.1 and the Stock by Attributes module is no longer working correctly. Customers are placing orders for items where the stock is zero. I've installed the most current version of the module 4.5. The host is running PHP5. Does anyone know if the module is compatible with PHP5?

The store is obviously live and my client is very understandable but its something I would love to get resolved for her.

Thanks in advance for any info or suggestions you can offer.

In certainly works for PHP5. Both our development machines and test server only have PHP5.

I'd double check the files listed in the mod's documentation. In each case where I've been able check on sites with the symptoms that you describe, it has turned out that vital files weren't installed properly, or have been overwritten by an upgrade or another mod. The order.php class would be the place to start.